1. Field
This disclosure relates generally to data processing systems, and more specifically, to data processing systems with protocol determination circuitry.
2. Related Art
The power provided to an integrated circuit, such as to a system on a chip (SoC), is, in many cases, provided by a power management integrated circuit (PMIC). The integrated circuit provides a power request signal to request that the PMIC either power on or power off the IC. Different types of PMICs are designed to respond to different protocols which define different types of signaling mechanisms. For example, one PMIC may interface with a toggle-type switch. In order for this type of PMIC to properly interface with the IC, the power request signal must be a toggle-mode signal. Another type of PMIC may interface with a pulse-type switch. In order for this type of PMIC to properly interface with the IC, the power request signal must be a pulse-mode signal. Therefore, it is necessary for an IC to know the type of PMIC in order to appropriately interface with the PMIC. However, at the time of design, it is unknown what type of PMIC might be used to interface with the IC. While pins are typically used to provide configuration information to ICs, pin counts are typically tightly controlled. Therefore, adding an additional pin to an IC in order to provide the PMIC type can be cost prohibitive. Therefore, a need exists for an improved interface to PMICs which can handle different types of PMICs and does not require additional pins.